The proposed project is mainly a characterization of the chemical changes that accompany diabetes and cataract in the human lens capsule. The amino acid and carbohydrate composition of lens capsules and their contents of glycosylated hydroxylysines will be determined. The composition studies will expand the very limited data concerning chemical changes in the lens capsule that occur in diabetes and cataract and will allow comparison with the conflicting reports of changes accompanying diabetes in the kidney glomerular basement membrane. Determination of the solubility of capsules in denaturing agents before and after reduction and alkylation of cystine residues and electrophoretic spearation of soluble components will help determine the importance of disulfide crosslinks in the membrane. With regard to diabetes, the extension of these studies to other basement membranes, such as those in the small blood vessels of the retina, will provide a basic understanding of the disease in terms of systemic biochemical changes, as opposed to local changes. During the course of this project, work on basement membranes from the retina will be continued.